They are a sweet pair. Though I remember in the first set of the Sailor Moon dubs they were not a couple...they were turned into cousins. *shrugs* Why that is better than them being a couple I will never understand lmao.
Well you have two dubs to choose from, if you're not a fan of reading subtitles. The one from the 90's (DiC) and the re-dubs (Viz). The one from the 90's has some changes and does not have the final season, Sailor Stars dubbed. The newest dub (Viz), I am not to sure how far along the dub is since I only saw the first half of season 1.
For the 90's dub the main characters voices sound completely different where as the new dub have the characters voices sound a bit similar (at least in comparison with the DiC version).
I guess it really depends on your taste. The DiC dub was made with kids in mind (thus getting censored) where as the Viz dub seems like it's targeted to an older audience (no censorship).
After that there is Sailor Moon Crystal; which I hear is being made to match the manga? I haven't seen it but I have heard someone recommended watching the original series and than watch Sailor Moon Crystal.